Occupational Disease Surveillance: Occupational Asthma

In 1987, the National Institute for Occupational Safety and
Health (NIOSH), CDC, initiated the Sentinel Event Notification
System for Occupational Risks (SENSOR) (1), a pilot project
conducted in association with state health departments. A goal of
SENSOR is to improve the reporting and surveillance of
work-related health conditions, including occupational asthma. Of
the 10 states* participating in the SENSOR program, six
(Colorado, Massachusetts, Michigan, New Jersey, New York, and
Wisconsin) have identified occupational asthma as a condition
targeted for surveillance. This report describes the
implementation and early results of occupational asthma
surveillance in Michigan, Colorado, and New Jersey, whose
programs share certain features.

SENSOR programs in each of these three states receive
occupational asthma case reports by telephone from any
health-care provider in the respective state. Information about
the surveillance activity has been disseminated to groups of
"sentinel providers" (such as allergists and pulmonary and
occupational medicine specialists) who are most likely to
encounter occupational asthma in their clinical practices.
Characteristics of the case report (including its congruence with
the surveillance case definition (see box), the number of
co-workers with exposures similar to those of the reported
case-patient, and the number of co-workers with respiratory
symptoms) determine priorities for follow-up workplace
investigations conducted by the SENSOR program personnel. Each
program sends to reporting physicians summaries of worksite
investigations conducted in response to cases they have reported.
To assist physicians in the evaluation of possible cases, the
programs may provide other services such as peak flow meters (New
Jersey and Colorado) or radioallergosorbent testing (Michigan).
In addition, all three programs actively collaborate with
academic occupational medicine programs in their states.

Michigan. In Michigan, an occupational disease reporting law
was already in effect when the SENSOR program started. With the
implementation of SENSOR, physician-education efforts and case
follow-up were enhanced and focused on a few target conditions,
including occupational asthma. Consequently, the number of
occupational asthma reports increased sharply, from 18 during
1984-1986 to 101 cases reported from September 1988 through
August 1989. Cases have been reported in persons who worked in a
variety of exposure settings, and case follow-ups have led to the
recognition of at least one new setting for occupational
asthma--sugar beet pulp processing. Thus far, at eight worksites
where investigations have been completed or are in progress,
employee interviews have identified 97 co-workers of reported
patients with symptoms suggestive of occupational asthma.

Colorado. In Colorado, voluntary reporting of occupational
asthma cases started in October 1987; in August 1988, state
health regulations were modified to make occupational asthma and
occupational hypersensitivity pneumonitis reportable conditions.
From October 1987 through December 1989, Colorado SENSOR received
87 case reports of occupational asthma and 21 case reports of
hypersensitivity pneumonitis. In Colorado, the SENSOR program
gives health-care providers a mechanism to report unusual
clusters of occupational illness. For example, from two case
reports received in Colorado, a cluster of 14 cases of probable
hypersensitivity pneumonitis was identified among workers at an
indoor swimming pool; follow-up investigation is under way.

New Jersey. New Jersey implemented voluntary reporting of
occupational asthma in 1988. From June 1988 through October 1989,
the New Jersey SENSOR program received reports of 66 possible
cases of occupational asthma. Seven of the first eight worksites
investigated had inadequate engineering controls; at these sites,
35 co-workers of possible case-patients had work-related
respiratory symptoms.
Reported by: RE Hoffman, MD, State Epidemiologist, Colorado Dept
of Health. KD Rosenman, MD, College of Human Medicine, Michigan
State Univ, East Lansing; F Watt, Michigan Dept of Public Health.
M Stanbury, MSPH, New Jersey Dept of Health. Div of Respiratory
Disease Studies and Office of the Director, National Institute
for Occupational Safety and Health, CDC.

Editorial Note

Editorial Note: Asthma caused by occupational exposures has been
recognized for nearly 3 centuries (3), but the true incidence and
prevalence of work-induced asthma remain uncertain. More than 200
agents have been associated with workplace asthma (5), and the
classes of agents implicated include certain microbial products
(e.g., Bacillus subtilis enzymes in the detergent industry),
certain animal proteins (e.g., urine protein divided by ander
from laboratory mammals), certain plant products (e.g., wheat
flour), and certain industrial chemicals (e.g., toluene
diisocyanate). Occupational asthma is an increasingly important
cause of respiratory impairment; it can persist for years, even
after termination of workplace exposures (6). Early recognition
is particularly important because a more favorable prognosis is
associated with a shorter duration of symptoms before diagnosis
(7) and because prompt removal from further exposures to the
offending agent is beneficial. Fatal cases have been reported
when workplace exposures continue (8). Identification of
occupational asthma can also lead to recognition of affected
co-workers, identification and correction of inadequate worksite
exposure controls, and discovery of new causes of occupational
asthma (9).

Early experience in Michigan, Colorado, and New Jersey
indicates that physician reporting of occupational asthma can be
used to identify workplaces with remediable health hazards. This
approach may improve surveillance of occupational asthma and
provide opportunities for primary and secondary prevention.

To facilitate provider-based surveillance of work-related
conditions and to enhance uniformity of reporting in the states,
NIOSH periodically disseminates recommended surveillance case
definitions for selected occupational diseases and injuries.
Because these definitions are designed for surveillance-related
functions, they may differ from those used for other purposes,
such as determining workers' compensation or level of disability.
The reporting guidelines and case definition for surveillance for
occu- pational asthma** (see box) are recommended for
surveillance of work-related asthma by state health departments
receiving reports of cases from physicians and other health-care
providers.

Smith AB, Castellan RM, Lewis D, Matte T. Guidelines for
epidemiologic
assessment of occupational asthma. J Allergy Clin Immunol
1989;84:794-805.
*California, Colorado, Massachusetts, Michigan, New Jersey, New
York, Ohio, Oregon, Texas, and Wisconsin.
**This definition was reviewed and approved by a panel of
consultants convened by NIOSH that comprise the Surveillance
Subcommittee of the NIOSH Board of Scientific Counselors: H
Anderson, MD, Wisconsin Department of Health and Social Services;
M Cullen, MD, Yale University School of Medicine; E Eisen, ScD,
Harvard School of Public Health; R Feldman, MD, Boston University
School of Medicine; J Hughes, MD, University of California, San
Francisco; MJ Jacobs, MD, University of California, Berkeley; K
Kriess, MD, National Jewish Center for Immunology and Respiratory
Medicine; J Melius, MD, New York State Department of Health; J
Peters, MD, University of Southern California School of Medicine;
D Wegman, MD, University of Lowell.

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